Polymer extrusion assembly and method for the detection of failure of cutter blades in polymer extrusion assembly

Abstract

The present invention relates to a polymer extrusion assembly and method for the detection of failure of cutter blades in polymer extrusion assembly, the assembly comprising: an extruder plate, a rotatable cutter assembly, a structured light, a detection mechanism, a reconstructing mechanism, and an analyzing mechanism capable of analyzing said image. The present invention allows for online condition monitoring of both the die plate and the knife set.

1 . A polymer extrusion assembly, the assembly comprising:
 an extruder plate that includes an inner face and a front face and at least one die opening;   a feed arrangement designed to feed polymer material towards said inner face of said extruder plate to cause said material to at least partially pass through said at least one die opening;   a rotatable cutter assembly that includes a least one cutter blade, said cutter assembly design causing said cutter blade to move so as to at least partially cut said material passing through said at least one die opening in said extruder plate, said cutter blade positioned at least closely adjacent to said front face of said extruder plate;   characterized in that said polymer extrusion assembly further comprises:   a structured light source for irradiating one or more of the at least one cutter blade, the front face of said extruder plate, and the interface between the at least one cutter blade and said front face of said extruder plate;   a detection mechanism capable of detecting the light reflected from one or more of the at least one cutter blade, the front face of said extruder plate, and said interface;   a reconstructing mechanism capable of reconstructing the detected light image; and   an analyzing mechanism capable of analyzing said image.   
     
     
         2 . The polymer extrusion assembly according to  claim 1 , wherein the detection mechanism comprises a camera. 
     
     
         3 . The polymer extrusion assembly according to  claim 1 , wherein said analyzing mechanism comprises a memory database in which images of each of said cutter blades, said front face of said extruder plate, and said interface between the at least one cutter blade and said front face of said extruder plate are stored. 
     
     
         4 . The polymer extrusion assembly according to  claim 3 , wherein said analyzing mechanism further comprises means for comparing:
 an actual image of said cutter blade with an image of said cutter blade stored in said memory database; and/or   an actual image of said front face of said extruder plate with an image of said front face of said extruder plate stored in said memory database; and/or   an actual image of said interface between the at least one cutter blade and said front face of said extruder plate with an image of said interface between the at least one cutter blade and said front face of said extruder plate stored in said memory database   and means for providing a signal on basis of said comparison.   
     
     
         5 . A method for the detection of failure of cutter blades in a polymer extrusion assembly, the assembly comprising:
 an extruder plate that includes an inner face and a front face and at least one die opening;   a feed arrangement designed to feed polymer material towards said inner face of said extruder plate to cause said material to at least partially pass through said at least one die opening; and   a rotatable cutter assembly that includes a least one cutter blade, said cutter assembly design causing said cutter blade to move so as to at least partially cut said material passing through said at least one die opening in said extruder plate, said cutter blade positioned at least closely adjacent to said front face of said extruder plate;   characterized in that the method comprises the steps of:   i) feeding polymer material toward said inner face of said extruder plate through said at least one die opening;   ii) cutting said material passing through said at least one die opening in said extruder plate;   iii) capturing an image of at least one of rotating cutter blade, the front face of said extruder plate, and the interface between the at least one cutter blade and said front face of said extruder plate;   iv) comparing the actual image of iii) with an image of the item under iii) concerned, said image being stored in a memory database;   v) providing a signal on basis of said comparison.   
     
     
         6 . The method for the detection of failure of cutter blades in a polymer extrusion assembly according to  claim 5 , wherein the method further comprises, before starting the extrusion process, capturing an image of at least one of a cutter blade, the front face of said extruder blade, and the interface between the at least one cutter blade and said front face of said extruder plate, and storing each image thus captured in a memory database as a reference for start-up condition. 
     
     
         7 . The method for detection of failure of cutter blades in a polymer extrusion assembly according to  claim 5 , wherein the method further comprises:
 before starting the extrusion process:   capturing an image of a chipped cutter blade and storing said image thus captured in a memory database as a reference for unacceptability of the chipped cutter blade; and/or   capturing an image of a used extruder plate and storing said image thus captured in a memory database as a reference for unacceptability of the used extruder plate; and/or   capturing an image of a chipped cutter blade, capturing an image of a used extruder plate, and comparing said image of a used extruder plate and said image of a chipped cutter blade and storing said image thus created in a memory database as a reference for unacceptability of the interface between the chipped cutter blade and said front face of said used extruder plate.   
     
     
         8 . The method for the detection of failure of cutter blades in a polymer extrusion assembly according to  claim 5 , wherein the method further comprises reconstructing a 3-D image of the images captured. 
     
     
         9 . The method for the detection of failure of cutter blades in a polymer extrusion assembly according to  claim 5 , wherein the method further comprises capturing images during cutter blade honing of the interface between the cutter blade and said front face of said extruder plate. 
     
     
         10 . The method for the detection of failure of cutter blades in a polymer extrusion assembly according to  claim 5 , wherein the method further comprises capturing images during cutter blade honing of the extruder plate. 
     
     
         11 . The method for detection of failure of cutter blades in a polymer extrusion assembly according to  claim 5 , wherein the method further comprises comparing said images captured during cutter blade honing with images captured as reference for start-up condition for providing a filter mechanism for eliminating the presence of any water. 
     
     
         12 . The method for the detection of failure of cutter blades in a polymer extrusion assembly according to  claim 11 , wherein the method further comprises, during the extrusion process, capturing an image of at least one of the rotating cutter blade, the front face of said extruder plate, and the interface between the at least one cutter blade and said front face of said extruder plate and applying said filter mechanism for eliminating the presence of any water for obtaining water filtered images of at least one of rotating cutter blade, the front face of said extruder plate, and the interface between the at least one cutter blade and said front face of said extruder plate. 
     
     
         13 . The method for the detection of failure of cutter blades in a polymer extrusion assembly according to  claim 12 , wherein the method further comprises applying a filter for the presence of polymer material on said water filtered images of at least one of rotating cutter blade, the front face of said extruder plate, and the interface between the at least one cutter blade and said front face of said extruder plate for obtaining water and polymer filtered images of at least one of rotating cutter blade, the front face of said extruder plate, and the interface between the at least one cutter blade and said front face of said extruder plate. 
     
     
         14 . The method for the detection of failure of cutter blades in a polymer extrusion assembly, according to  claim 13 , wherein the method further comprises comparing the water and polymer filtered images of at least one of rotating cutter blade, the front face of said extruder plate, and the interface between the at least one cutter blade and said front face of said extruder plate with the relevant images stored in a memory database as a reference for unacceptability and stored as a reference for start-up condition.